RANKING · 2010 CENSUS · 39 SHOWN OF 39

Most densely populated, Washington counties · 2010

Washington counties ranked by residents per square mile (2023). This list covers the 39 counties in Washington that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

RELATEDLargest by population Fastest growing Fastest shrinking Most sparsely populated Best broadband access Worst broadband access

YEAR1990 2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION DENSITYVS 2000

01King County, WAWA2,344,939913+11%

02Clark County, WAWA532,119677+23%

03Kitsap County, WAWA283,374636+8%

04Pierce County, WAWA946,288477+13%

05Island County, WAWA85,657377+10%

06Thurston County, WAWA304,261349+22%

07Snohomish County, WAWA870,656342+18%

08Spokane County, WAWA558,344267+13%

09Benton County, WAWA221,722103+23%

10Whatcom County, WAWA236,39295+21%

11San Juan County, WAWA18,57791+12%

12Cowlitz County, WAWA114,88590+10%

13Skagit County, WAWA132,97568+14%

14Mason County, WAWA71,16563+23%

15Franklin County, WAWA102,61263+58%

16Yakima County, WAWA259,18557+9%

17Walla Walla County, WAWA62,36146+7%

18Clallam County, WAWA78,20241+11%

19Grays Harbor County, WAWA78,14438+8%

20Asotin County, WAWA22,54534+5%

21Grant County, WAWA105,72733+19%

22Lewis County, WAWA88,06231+10%

23Chelan County, WAWA81,94125+9%

24Pacific County, WAWA24,35722−0%

25Douglas County, WAWA46,47321+18%

26Whitman County, WAWA48,51221+10%

27Kittitas County, WAWA48,80318+23%

28Stevens County, WAWA49,66818+9%

29Jefferson County, WAWA33,97017+15%

30Wahkiakum County, WAWA4,87315+4%

31Klickitat County, WAWA24,33111+6%

32Adams County, WAWA21,48810+14%

33Pend Oreille County, WAWA14,4579+11%

34Okanogan County, WAWA45,2308+4%

35Skamania County, WAWA12,6697+12%

36Columbia County, WAWA4,1415+0%

37Lincoln County, WAWA11,9825+4%

38Ferry County, WAWA7,5173+4%

39Garfield County, WAWA2,4163−5%

SHOWING 1–39 OF 39

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UPDATED 2026-06-02 · DATA: US CENSUS BUREAU ACS 5-YEAR ESTIMATES